One type of image-forming device well known in the art has developing cartridges that can be detachably mounted in the image-forming device. This type of image-forming device, such as that disclosed in Japanese unexamined patent application publication No. 2001-272899, includes image-forming units, which have rollers such as photosensitive drums and which are removed from the body of the image-forming device in a direction parallel to the axes of these rollers.
In an image-forming device disclosed in United States patent application publication No. 2004/165910A1, a cover is positioned on the body of the image-forming device above the developing cartridges. The cover rotates about hinges in order to cover or expose the developing cartridges. When exposed, the developing cartridges can be removed from the image-forming device.